Vehicle security systems are proposed to prevent unauthorized use of a stolen vehicle by immobilizing the stolen vehicle when the vehicle is stolen with its authorized (normal) key.
In the case of robbery of a vehicle having such a vehicle security system along with its authorized key, when the owner of the vehicle reports the robbery to a base station, the base station transmits a signal representing a drive prohibition request for the engine of the vehicle to the vehicle using wireless communication. Upon receipt of the signal representing a drive prohibition request, the engine is prohibited from being started (for example, JP-A-2003-146185).
In this vehicle security system, for releasing prohibition control based on a signal representing a drive prohibition request transmitted from a base station, a releasing unit may be provided in the vehicle to release the prohibition when the releasing unit is operated. In this case, power must be supplied to the releasing unit to enable the same when a user wishes to release the prohibition. However, when power is normally supplied to the releasing unit, power consumption increases.